Compression-tester



Hoff/Java L. M. KNAPP.

COMPRESSION TESTER.

APPLICATION FILED MAR. I, 1919.

Patented Apr. 20, 1920.

unirn@ sr ritirati-T GFF 10E Application led March 1,

To all whom t may concern:

Be it known that 1, Lne M. luarr, a citizen of the IUnited States, residing at Wellsville, in the county of Allegany and State ot New York, have invented certain new and useful Improvements in Compression-desters, of which the following is a speciication. This invention has relation to testing de- ,Vices with particular reference to the testing of the compression of internal combustion engines, and has for an object to provide a device to be inserted into the spark plug opening of the cylinder with means for indicating in pounds per square inch the compression of the cylinder under examination.

In addition to the foregoing, this invention comprehends improvementsin the details of 4construction and arrangement of parts, to be hereinafter described and par?l ticularly set forth in the appended plaim.

1n the accompanying drawings in which similar and corresponc ing'parts are designated by the same characters of reference throughout the several views in which they appear. ,Y

Figure 1 is a view in section ot a device constructed in accordance with myinvention for testing compression.

Fig. 2 is a view in plan of a holder Jfor the testing device.

With reference to the drawings, 10 indi cates the engine cylinder having the threaded spark plug opening 11, and 12 a hollow threaded plug to enter the opening. The upper end of the plug is formed with a hexagonal wrench engaging portion 13, and the upper surface of said portion is formed with a substantially semi-circular lange 1l having an undercut recess 15. l

1n connection with the plug 1:2 `I may use a conventional form ot pneumatic tire pressure gage consisting of a tubular casing 16 having a flange '17 at its lower end to enter the recess 15, the casing being inserted beneath the flange laterally. A tubular indicator 18 sli les in the casing and interposed between th?. upper end of said member 18 and the lower end of the casing 16 is a coiled spring 19. A rubber easing Q0 is inclosed within the spring,` and communicates at its lower end with an openingl at the lower end of the casing 16, said-opening in turn coinmunicating with the interior of the plug 12.

In operation, pressure within the cylinder as a result of movement of the piston on a Specification of Letters loaLent.

diera. seran No. 280,075.

compression stroke will cause the rubber casing to expand and push the indicator 18 upwardly against the tension of the sprinff 19. The spring and rubber casing may co lapse upon the succeeding exhaust stroke but the indicator 18 will remain at its moved v position, thus indicating by the proximity to the upper end of the casing 16 of graduar tions on itsV surface the amount of pressure within the cylinder.

Thus,"\'vith my testing device the compres` sion of any automobile engine may be tested to determine the pressure of leaky piston rings, cylinder cracks or other faults. Other uses may readily occur to those skilled in the art to which this invention appertains.

Thile I have illustrated and described my invention with some degree of particularity, realize that in practice various alterations therein may be made. l therefore. reserve the right and privilege of changing the form ot' the details oi construction or otherwise altering the arrangementv of the correlated parts withoutdeparting fronrthe spirit of the invention or the scope of the appended claim.

Having thus described my invention, what I claim as new and desire to secure by United States Letters Patent is:

. A compression tester comprising a plug having a longitudinal explosion passage extending therethrough, and having an eX- tcrior portion threaded, a hexagonal enlargement at one end thereof, an annular radial flange at the termination of said enlarged portion and interiorly thereof, a semicircular flange formed on the end face of said hexagonal portion having its walls undercut or reset concentrically relative to the explosion opening of the plug, and a gage comprising a stationary element and a mo fable element, and an annular ilange on one endv of said stationary element adapted to be inserted within the undercut] portion of the semicireular flange, the latter serving to engage the semi-circular flange `to secure.

the gage in place and to aline the center of the gage with the center of the explosion opening ot the plug for the purpose. set fort-h.

In testimony whereoif` I afiiX my `signature in presence of two witnesses.

LE() M. KNAPP. [n s] lllitnesses J. FARNUM BROWN. 

